Solutions / City-Wide Solutions

Citywide Solutions

Cities have many solutions available to reduce air pollution quickly and at scale. See which solution areas are right for your city.

“Cities can reduce both air pollution and short-lived climate pollutants such as black carbon and ozone through a range of measures that benefit health very immediately and climate in the near term.”

Dr. Carlos Dora, Coordinator of WHO’s air quality, public policies and health work.

Solutions for Transport

01 - Solutions for Transport Strong public transit systems are the backbone for making our cities “trim”, energy efficient and more livable. Cities built primarily around car travel quickly become sprawling and “obese” -- gobbling up land in highways and parking lots, generating more pollution, and fostering unhealthy lifestyles. Pedestrian- and cycle-friendly cities with separated networks for walking biking and mass transit make commuting safer, easier, healthier, and less expensive.
  • Walking & cycling paths

    Walking and cycling networks make trips by foot or bicycle safer and more accessible, preventing pollution from vehicles, traffic injuries, and promoting better health through physical activity.

  • Efficient mass transit

    Shifting people to more efficient forms of transport, including bus rapid transit, light rail and other forms of shared transportation dramatically reduces air pollution by cutting down on private vehicle use and emissions.

  • Emission standards

    Raising emissions standards for all vehicles takes heavy polluters off the road and drives market pressures for cleaner vehicles, as well as innovation for cleaner technologies. Reducing high-sulfur fuels in many emerging economies is an important first step.

  • Soot-free vehicles

    Retrofitting particle filters onto older diesel vehicles, or adopting newer soot-free vehicles and technologies, can drastically reduce emissions from heavy-duty diesel buses, trucks and passenger vehicles, which are among the heaviest emitters of black carbon.

Tolls for high pollution days (Oslo)

Oslo plans to increase tolls on its heavily congested E18 highway on days with heavy air pollution as studies show that this increase has the potential to cut nitrogen dioxide (NO2) emissions in Oslo through a 27% reduction in car traffic.

Sticker system curbs high polluters (Paris)

Private vehicles more than 20 years old  will not be allowed into center city areas of Paris during peak travel hours in a new sticker system for motorists.. This is just the first step in a broader plan to phase out much of the vehicle traffic entering the center city, in favor of pedestrian, bike and transit.

World’s highest urban cable cars (La Paz)

By connecting La Paz, Bolivia to the nearby mountaintop city of El Alto, the cable cars have cut commuting time from hours in traffic to less than 10 minutes in traffic. Two more lines are being built to further reduce road congestion.


Solutions for Waste Management

02 - Solutions for Waste Management Landfills account for 11% of the world’s methane emissions, and municipal waste is expected to nearly double by 2025. Furthermore, an estimated 90% of wastewater in developing countries is discharged untreated or partially treated. Better waste management programs are integral to ensuring our communities don’t suffer as a result, both on a local and global level.
  • Landfill gas recovery

    Landfill gas recovery is an innovative, renewable energy option that actually harnesses harmful landfill emissions rather than allowing them to enter the atmosphere or our lungs.

  • Improved wastewater treatment

    Improving wastewater treatment and sanitation provisions, both in the home and in industry, can make an enormous difference in reducing infectious disease risks.

Clarke Energy in the UK is using landfill gas to supply more than 2.7million EU homes

In addition, by capturing landfill gas instead of emitting it directly into atmosphere, they can reduce greenhouse gas emissions by about 40 million tonnes CO2 equivalent each year.

Clean energy from sludge bio-digesters (Santiago)

Large and centralized wastewater treatment plants in Santiago are harvesting methane emissions during wastewater treatment. The process uses built-in bio-digesters or sludge pyrolysis to process the methane and produce natural gas or electricity.


Household air & pollution

03 - Solutions for Household air & pollution Nearly 60% of premature deaths from household air pollution are among women and children who spend hours around sooty cookstoves burning wood, coal and kerosene. Shifting to cleaner stoves can have a domino effect of benefits – reducing black carbon emissions as well as the time spent by women and girls in gathering fuel.
  • Low-emission stoves and fuels

    Cleaner-burning biomass stoves and other low-emission fuels or stove types improve air quality in the home and the community, and lower risk of burns or other injuries.

  • Improved lighting

    Electric lighting, including PV solar rooftop panels, reduces reliance on kerosene lamps that emit heavy concentrations of harmful black carbon and other air pollutants.

  • Passive building design principles

    Reducing the need for extra heating or cooling by designing homes that take advantage of the sun’s natural warming and fresh air ventilation for cooling can help minimize a home’s air pollution and carbon footprint.

CDM urban housing energy upgrade (Cape Town)

The project employed local residents to retrofit over 2300 homes in Kuyasa, Cape Town, South Africa, with solar hot water heaters, insulated ceilings and energy-efficient lighting. The improved insulation is expected to help reduce the high rates of chronic bronchitis and childhood asthma due to cold and damp conditions, as well as heating with paraffin. Solar-heated water improves kitchen sanitation and hygiene conditions, while putting their homes on a more sustainable footing for the future. More


Solutions for Energy supply

04 - Solutions for Energy supply Oil and gas produce 25% of the world’s methane emissions. Flaring, the burning of uncaptured gas during production, emits harmful black carbon. Better control of fugitive emissions and capturing flared gas as fuel helps limit emissions from current oil and gas production in the short-term, while the shift to renewable energy sources can ensure a cleaner, healthier future in the long-term.
  • Renewable power supply

    Renewables directly improve air quality while slowing climate change. For example, rooftop PV solar systems in off-grid rural areas or fast-growing cities with unreliable energy supply is a clean, and cost-effective alternative to heavily polluting portable diesel generators.

  • Diesel replacement

    The fine particles and black carbon emitted by diesel vehicles and engines can be virtually eliminated through technologies that are already present on half of new heavy-duty vehicles sold today.

Diesel bus filter incentives (Santiago)

The city began a program to install diesel particulate filters (DPF) on buses and offering incentives for bus owners to retrofit their vehicles with filters. Until higher emission standards were mandated in 2010, this served as an effective and low-cost means of reducing air pollution without scrap page while putting the city on the path to a full soot-free bus fleet.


Solutions for Industry

05 - Solutions for Industry With more people living in cities, brick production and other heavy industry continue to contribute to air pollution. New technologies and practices are increasingly being introduced so that even as our cities grow, air pollution doesn’t grow with it.
  • Improved brick kilns

    Kilns used for firing bricks are heavy polluters of black carbon and put workers at increased risk for respiratory illness, but new kilns are being used that can cut emissions by up to half.

  • Improved coke ovens

    Coke ovens used to produce some metals emit toxins that can increase cancer risk. However, emissions can be captured for power generation and help minimize what is entered into the atmosphere

  • Fugitive emission control

    Fugitive emissions occur from leaks or the burning off of excess gas through flaring. Ongoing maintenance and new monitoring and detection technology can limit unnecessary emission from industry.

Building back with cleaner kilns (Nepal)

More energy-efficient brick kilns, designed and built after Nepal’s 2015 earthquakes, have demonstrated a 60% decrease in particulate emissions and reduced coal consumption by 20-30%. So far nine kilns out of the 350 damaged have been entirely rebuilt with the new designs, while others underwent upgrades. Brick production and quality has also increased and workers are experiencing less exposure to dust and pollution. See how engineers, scientists and local entrepreneurs are working together to rebuild a cleaner, safer and less polluting industry.



New kiln technology (Bangladesh)

A brick kiln technology developed in Germany uses half the amount of coal during brick production, trapping particles inside the bricks themselves to prevent them from entering the atmosphere, and thus protecting factory workers from inhaling health harmful black carbon and other particulate pollutants. Widespread adoption of the technology in Bangladesh is expected to cut both black carbon emissions as well as reducing long-lived CO2 emissions equivalent to emissions from nearly 16,000 American vehicles a year. More here


Solutions for Food & Agriculture

06 - Solutions for Agriculture The agricultural revolution of the past 50 years has dramatically increased food supplies. At the same time, livestock production has become a major driver of climate change due to its heavy water, feed and energy requirements, and a major source of methane emissions from ruminant animals like cattle. Rice production in continuously flooded fields is also a major source of methane, which is has immediate climate warming impacts far more powerful than longer-lived CO2.
  • Alternate "wet-dry" irrigation

    Intermittently drying out rice paddies, which traditionally were flooded year-round, can significantly cut methane emissions, while also reducing breeding grounds for disease-bearing mosquitoes and other vectors.

  • Improved manure management

    Waste “digestors” extract methane from livestock waste and sewage converting emissions into a clean energy source. Manure can also be used as fertilizer to improve crop production, moderate methane release and prevent the spread of disease.

  • Reduced open burning

    Waste management programmes to prevent open burning from crop waste and domestic and municipal waste such as paper and plastics, avoids dangerous pollutants from being released into the air, including black carbon.

  • Healthier food production

    Policies that promote diets rich in plant-based foods, particularly among middle- and high-income populations with plentiful food choices, can lower healthcare costs while reducing methane emissions from livestock production.

  • Reduced food waste

    Separating and composting biodegradable food waste reduces methane emissions from landfills, and can also be used as a source of fertilizer for local agriculture.

Incentive programs for composting (Penang)

Penang’s composting project creates incentives for households to separate their organic waste. It is then used as fertilizer and avoids being sent to landfills where it contributes to methane emissions. More about Penang’s waste challenges and composting program here